1. Field of the Invention
This invention relates generally to clips and clamps, and more specifically to low-profile spring clips adapted for use in surgical procedures.
2. Discussion of the Prior Art
Surgical clips and clamps are commonly used to occlude body conduits such as blood vessels. These clips and clamps typically have parallel jaws that are moveable between an open position and a closed position. Ratchet clips, such as those disclosed by Blake in U.S. Pat. No. 3,510,923, include a ratchet mechanism that functions to hold the jaws in the closed position. Other clips include extension or compression springs for biasing the jaws to the closed position. Representative of this art is U.S. Pat. No. 4,931,058. Low-profile clips include tabs, which are moveable to operate the jaws as disclosed by applicant in application Ser. No. 08/949,126, filed on Jun. 17, 1999, and entitled Low-Profile Surgical Clip, which is incorporated herein by reference.
The low-profile clips typically include a telescoping barrel with a pair of jaws on one side, and a pair of actuating finger tabs on the other. Closing the tabs opens the jaws against the bias of a spring disposed in the telescoping barrel. In the past, the telescoping barrels have been formed with a shape complimentary to that of the cylindrical spring. Although the cylindrical barrel design has facilitated assembly of the clip, unfortunately it has not contributed significantly to the angular stability of the jaws. As a consequence, the jaws have tended to scissor, rather than maintain their preferred parallel relationship.
The guidance ratios of the telescoping barrels has also been somewhat limited in the past. This guidance ratio is commonly determined by dividing the guidance length by the radial width of the smallest telescoping member. In the past, guidance ratios for a low-profile construction have been generally limited to about 1.0.
Of course, it is always desirable to achieve an improved construction requiring a fewer number of parts. Where this can occur in combination with an easier method of assembly, manufacturing costs can be greatly reduced. It is always desirable to decrease the flexibility of a clip in order to prevent scissoring and to maintain the desired parallel relationship of the jaws. Providing increased guidance ratios is also desirable.